The present disclosure herein relates to semiconductor devices, and more particularly, to nonvolatile memory devices.
Semiconductor memory devices may be classified into volatile memory devices and nonvolatile memory devices. The volatile memory devices have a volatile characteristic that loses all data stored therein when power is cut off. The volatile memory devices may include DRAM devices and SRAM devices. Nonvolatile memory devices have a characteristic that it retains stored data even if power supply is interrupted. Examples of the nonvolatile memory devices may include PRAM devices, MRAM devices and/or flash memory devices.
Flash memory devices may electrically rewrite or erase data. Such a flash memory device may be classified as a NOR type flash memory device or a NAND type flash memory device. The NOR type flash memory device enables high-speed random access, and thus, it may be widely used for a device in which high-speed operation is required. The NAND type flash memory device has faster programming and erasing speed and advantage of easy high integration. Thus, the NAND type flash memory may be used for a large-capacity memory device.
As the semiconductor industries are developed rapidly, line widths and/or distances of patterns for realizing nonvolatile memory devices are being reduced more and more. Accordingly, reliability of the nonvolatile memory devices is being reduced. As semiconductor and electronic industries develop, high-integration and superior reliability of nonvolatile memory devices are being required more and more.